Butt welding of sheet metal panels, particularly in the automotive restoration and repair field, typically utilizes panel clamps to secure two panels together parallel to each other and with a defined gap, approximately the thickness of the sheet metal. Typically, as shown in the prior art of FIG. 1, the extruded clamp secures approximately 1″ of the panel. However, the backside clamping pin 3 does not extend on either side of the extruded frame. The gap between the panels is open, with no backing provided. The prior art shown in FIG. 1 provides adequate spacing and some level of support of the two adjoining pieces of sheet metal but does not provide an integral means of backing the weldment to prevent blowout of the weld and maintain tighter panel coplanarity along the length of the panel. Additional copper backing apparatus are available that are either hand held or magnetically held in place behind the panels to assist the welding operation. Often, it is impossible to reach behind the panel to hold the backing piece in place, particularly for a single operator. Magnetic backing plates do not provide additional structural support or adequate thermal dissipation and may negatively affect the quality of the weld itself.
Other examples of prior art also do not satisfy the viability of the present invention. Brandenburg, et al, in U.S. Pat. No. 3,063,393, present a welding fixture intended for larger production welding and in particular, an apparatus designed for hot short materials (material subject to cracking upon cooling). The apparatus is also too cumbersome and complex for the intended purpose of this invention.
In U.S. Pat. No. 3,272,881A, Kiefer is presenting an invention to aid the weld operator in holding a patch panel in place with the use of a “third hand” mechanism. It does not address butt welding nor does it provide clamping or thermal dissipation of the weld heat.
The invention noted in U.S. Pat. No. 5,158,225 is an example of a backing plate in its simplest form. It is simply a piece of copper on a handle that is held in place by the operator or an assistant. This tool provides no clamping support and is only useful for small holes, short welds and where access by the operator to an assistance to reach the backing location is possible.
U.S. Pat. No. 5,584,427 is an invention the is designed to aid in the formation and concentration of shield gas on the back-side of a welded joint in pipes. It does not provide clamping or gap control.
US2010/03437/4 A1 (now U.S. Pat. No. 8,393,529 B2) is used in a process known as friction welding. Although copper is used as a backer, the banker is not configured in the same manner, not could this apparatus be utilized for conventional butt welding in the intended manner and applications.
None of the prior art apparatus' are capable of being implemented in the manner of the present invention that would provide the operator with simple hands free welding operation with secure aligned panels and the benefit of a copper backer to secure the panels in a proper position for optimum welding. Few of the prior art inventions provides the copper backer as part of the clamping mechanism. Those that do are too large and cumbersome for this application.